700R4 TCC Lockup
Thread Starter
Instructor
Joined: Jul 2001
Posts: 126
Likes: 0
From: Miami, FL, USA
700R4 TCC Lockup
Still trying to figure out whats wrong with my transmission. I noticed that the TCC locks up way to early. It comes on right after 2nd gear, at around 17 mph part throttle. Is this correct? I know i can put in the switch from Ecklers, but I would like it to work correctly without doing that. Could i have the wrong PROM?
Thread Starter
Instructor
Joined: Jul 2001
Posts: 126
Likes: 0
From: Miami, FL, USA
Re: 700R4 TCC Lockup (tan85vet)
Also, when the car is cold, if i step on it and it downshifts (starting from lets say 25), it will rev up more because the lockup feature is still off in the ECM, but if i do this same thing when the car is warmed up, I think the TCC stays locked up and the RPMs dont come up...it seems like its being bogged down.?
Pro
Joined: Sep 2001
Posts: 743
Likes: 4
From: Guyton GA
Re: 700R4 TCC Lockup (tan85vet)
A automatic trans may not perform perfect until up to temp. I recommend warming the engine/trans before getting in the throttle. Odds are there is probably nothing wrong with your trans. A fresh filter and quality oil (not Walmart Tech2000) can make a world of difference.
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: 700R4 TCC Lockup (merrick)
Mine is doing essentially the same thing.
(91 Vette, Raptor 700R4, 2600 RPM stall)
Seems like the transmission just can't wait to run through the gear and get the torque converter locked up.
The locked torque converter is KILLING my performance.
I can touch the brake which cancels torque converter lockup and it feels like another lower gear.
THERE IS SOMETHING WRONG.
I just don't know what it is . . yet.
Anybody out there KNOW what may be causing this.
With all due respect "it ain't a cold transmission problem".
My 84 is basically the same tranny and it doesn't act this way at all.
ANYBODY?
(91 Vette, Raptor 700R4, 2600 RPM stall)
Seems like the transmission just can't wait to run through the gear and get the torque converter locked up.
The locked torque converter is KILLING my performance.
I can touch the brake which cancels torque converter lockup and it feels like another lower gear.
THERE IS SOMETHING WRONG.
I just don't know what it is . . yet.
Anybody out there KNOW what may be causing this.
With all due respect "it ain't a cold transmission problem".
My 84 is basically the same tranny and it doesn't act this way at all.
ANYBODY?
Thread Starter
Instructor
Joined: Jul 2001
Posts: 126
Likes: 0
From: Miami, FL, USA
Re: 700R4 TCC Lockup (VetNutJim)
Yup yup, u couldnt have put it better...it cant wait to get through the gears. I drove a friends 88 and it works just right....and with 200k miles and no rebuild yet, go figure. Somebody's gotta know how to fix this.
Burning Brakes
Joined: Nov 2000
Posts: 1,012
Likes: 1
From: Bowie MD
Re: 700R4 TCC Lockup (tan85vet)
Wow - I got exactly the opposite problem. Mine stays too long in the gears. The new LevelTen transmission and Protorque convertor can be locked up via the port under the steering column with a scanner tool, but wont lockup while driving. Gas mileage at 18mpg. The tranny guy says the trans is fine, so is the wiring as far as he could trace it. The Chip People, (Formato) claim the chip is set to lock up by VSS (vehicle speed sensor) at 50mph. The tranny people claim what is needed is for the D pin to be grounded. Wish I could find someone that could fix this for me.
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: 700R4 TCC Lockup (tan85vet)
The TCC will lock in second and stay locked if the TCC solenoid screen is clogged.
This is a VERY common problem on hi mileage TH700R4 transmissions.
Most recommend replacing the solenoid, but it can be cleaned. To clean the solenoid, you have to drop the trans pan and filter. Once the filter is removed, it will look like an electric relay that has exposed windings, just forward of the valve body. There are two 10mm screws that hold it in place. Remove the screws and work it out. You can clean it with brake parts cleaner.
It genereally indicates you need to service the trans fluid and filter.
This is a VERY common problem on hi mileage TH700R4 transmissions.
Most recommend replacing the solenoid, but it can be cleaned. To clean the solenoid, you have to drop the trans pan and filter. Once the filter is removed, it will look like an electric relay that has exposed windings, just forward of the valve body. There are two 10mm screws that hold it in place. Remove the screws and work it out. You can clean it with brake parts cleaner.
It genereally indicates you need to service the trans fluid and filter.
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Drifting
Joined: Nov 2001
Posts: 1,783
Likes: 2
From: Latham NY
Re: 700R4 TCC Lockup (tan85vet)
Don't buy the Eckler's switch, it is a waste of money. I have the same transmission and could not keep it in overdrive on the highway. GM corrected some problems with the transmission later on so you will need more than a shift kit. I got a Transgo shift kit from Probuilt.
[URL]http://www.pro-built.net/index.cfm/[URL]
It contained the updated GM valves. Talk to the owner and tell him your transmission problems and how you intend to drive and he will give you the kit with the correct parts. My transmission will hold any gear now until I want it to shift. Before, it would shift anyime it wanted too. I found it helpful to install a transmission drain plug. If the car hasn't been maintained, you will need to change the fliud several times to get out all the old fluid in the system. Good luck.
[Modified by Bluevette85, 10:21 PM 2/16/2002]
[Modified by Bluevette85, 10:22 PM 2/16/2002]
[Modified by Bluevette85, 10:22 PM 2/16/2002]
[URL]http://www.pro-built.net/index.cfm/[URL]
It contained the updated GM valves. Talk to the owner and tell him your transmission problems and how you intend to drive and he will give you the kit with the correct parts. My transmission will hold any gear now until I want it to shift. Before, it would shift anyime it wanted too. I found it helpful to install a transmission drain plug. If the car hasn't been maintained, you will need to change the fliud several times to get out all the old fluid in the system. Good luck.
[Modified by Bluevette85, 10:21 PM 2/16/2002]
[Modified by Bluevette85, 10:22 PM 2/16/2002]
[Modified by Bluevette85, 10:22 PM 2/16/2002]
Drifting
Joined: Sep 1999
Posts: 1,524
Likes: 1
From: King Ranch, 2015 GTR 2008 Z06 Viper Texas
Re: 700R4 TCC Lockup (corvette1990)
Its possible They sent you a non lock up tranny. Had the same thing happen when I installed my Hughes 2 years ago. I called them and they sent me the sollenoid, That solved the problem. Also make sure the new tranny has a vette governor or yours was installed.
Wow - I got exactly the opposite problem. Mine stays too long in the gears. The new LevelTen transmission and Protorque convertor can be locked up via the port under the steering column with a scanner tool, but wont lockup while driving. Gas mileage at 18mpg. The tranny guy says the trans is fine, so is the wiring as far as he could trace it. The Chip People, (Formato) claim the chip is set to lock up by VSS (vehicle speed sensor) at 50mph. The tranny people claim what is needed is for the D pin to be grounded. Wish I could find someone that could fix this for me.
Safety Car
Joined: Sep 2001
Posts: 4,153
Likes: 553
From: Glenbeulah Wi
Re: 700R4 TCC Lockup (tan85vet)
I had the same problem that you describe on my 1886. The transmission would lockup as soon as it shifted into second gear and the engine would chug and shudder until the rpm picked up. If I floored the car it would unlock but then it would not relock the convertor until I shut the car off and restarted it. This problem was driving me crazy and people told me it was suppossed to act that way? I then started expermenting with chips to improve my performance and by accident ended up fixing the transmission problem. It turns out my chip was the problem with the lockup convertor, I switched to a 1987 chip and the problem completely disappeared. It will now lockup at 42 MPH in four gear and unlocks when I floor it and then relocks once I start to cruise again. It made my car much more enjoyable to drive. By the way, I also tried chips from L-98 Firebirds and they worked better then my stock chip. The 1986 stock chip had the worst transmission lockup control out of all the chips I tried. I finally settled on a stock 1987 GTA 350 chip, it gave me the best 1/4 mile performance and transmission lockup control.
Intermediate
Joined: Jan 2002
Posts: 41
Likes: 0
From: perryton texas
Re: 700R4 TCC Lockup (bjankuski)
Had the same running thru the gears problem--But a TV cable adjustment fixed it --see my thread for more info-- http://forums.corvetteforum.com/zerothread?id=239130
Heel & Toe
Joined: Nov 2001
Posts: 19
Likes: 0
From: Ikaalinen
Re: 700R4 TCC Lockup (tan85vet)
Bjankuski wrote about chips.
I had same frustrating problem in my 85. There are two chips in 85 ECM. The SMALL one should be no. 1604 2438 in automatic car. I had 1604 2431 (manual trans chip) in my car. I changed it and now my 85 is really enjoyable to drive. The bigger chip in my car is original. Hope this helpsYou.
